What is the reaction involved in Holmes signal?
Answer & explanation
Correct answer: option 2
The reactions involved in Holmes signal are:
Ca3P2 + 6H2O → 2PH3 → P2H4 + P4O6 and CaC2 + H2O → C2H2
Calcium carbide and calcium phosphide both react with water to give acetylene and phosphine respectively. These gases burn to give the signal.